1. Technical Field
The present invention relates to diffractive optics elements having surface relief holograms, methods for manufacturing such diffractive optics elements, and electronic devices.
2. Related Art
The stated diffractive optics element is used, for example, as part of an illumination optical system in a projector. A hologram such as that disclosed in JP-A-11-161142, for example, which has a structure in which a hologram layer configured of a thermosetting resin or the like is provided upon a transparent substrate such as glass, can be given as an example of a diffractive optics element. Meanwhile, in recent years, laser light sources have begun to be used as light sources in projectors as well.
A surface relief-type computer generated hologram (CGH) can be given as an example of a diffractive optics element that can configure an illumination optical system in combination with the aforementioned laser light source. A surface-relief hologram that records only phase information is desirable as the hologram in an illumination optical system for a projector.
However, in the case where, for example, a thermosetting resin is used as the hologram layer, there is a problem in that because the resin has a low heat resistance temperature, a high-output laser beam for a high light flux projector being incident thereon will result in thermal deformation, discoloration, and so on, and as a result, the original performance can only be maintained for a short amount of time. There is a further problem in that it is necessary to ensure both a high level of transmissibility that can withstand even a high-output laser beam and a high level of heat resistance that can withstand heat generated when laser light is absorbed.